Comment: Why China needs help cutting its emissions

IN DISCUSSIONS over how to avoid dangerous climate change, two numbers are especially prominent&colon; 450 parts per million and 2 °C. These are, respectively, the upper “safe” concentration of carbon dioxide in the atmosphere, and the upper “safe” limit of average global temperature increase. The fear is that if we exceed either, the climate will pass an irreversible tipping point.

The world’s biggest emitter of CO2 doesn’t see the future in quite the same way. I recently visited several institutions in China and heard some rather different numbers – numbers that are not being aired in the west. They certainly don’t …